The idea of the 'whack-a-mole' game is that each time a mole's head appears above the parapet, you clobber it with a hammer and push it back down, the goal being to keep the playing field clear of moles. But no matter how hard you hit a mole, there always seems to be another one willing to risk being whacked.

Keeping your mobile phone bill down is very similar to a game of whack-a-mole. Just as you think that one set of charges has been reduced, some new charges pop-up somewhere else. And so it is with the abolishment of roaming fees in Europe. No longer will you have to pay any more than your standard fees for using your standard call package when travelling within the 28 European Union Member States. Remember though, this only applies to calling and texting home, and to using data. If you want to make a call to the restaurant down the road whilst you are staying in France, this is still an international call from the UK. So which mole is sticking its head above the parapet now?

Prior to the abolition of roaming fees, several mobile operators offered roaming packages which were designed to help travellers keep down the cost of roaming. Take Vodafone as an example. For those travelling to the EU 28, it had a package called 'EuroTraveller' which allowed you to use your home allowances for GBP3 per day. There was a secondary package called 'WorldTraveller' which allowed you to use your home allowances for GBP5 per day in another 60 or so countries. Both of these packages were optional and you could opt in and out willy-nilly. So if you didn't want to use your packaged in full, but just wished to send one text message, you could opt out (ideally before you travelled) and just pay the 30p or so rate for a text instead of GBP3, meaning that low users and high users could select a deal that was best for them.

So as of June 15 when EU roaming is free, Vodafone has introduced two new packages, 'Roam-Free' and Roam-Further'. Roam-Free allows you to use your UK package in the EU28 plus a few non EU-countries such as Iceland, Norway, Switzerland and Turkey at no additional charge. Roam-Further allows you to use your UK package in a further 60 countries (largely the same as the previous WorldTraveller package excluding, for some reason, the United Arab Emirates) for GBP5 per day. So it sounds the same, right? Wrong! The Roam-Further package is NOT optional. This means that if you travel to one of the 60 countries included in the list, such as Australia, Hong Kong, Thailand or the USA, and send a single text message to let someone back home know that you are OK, it will cost you GBP5. There is no way to opt-out of this package. So instead of costing 35p for that text, it will cost GBP5. And there's your new mole, peering out of its hole.

Just when you thought that roaming was going to be cheaper and easier, if you travel anywhere outside of the EU, the operators will now try and recoup their costs from you by charging more for roaming than they did before. Of course if you're a heavy user, not much has changed, but for most holidaymakers who just want to let someone back home know that they are OK, and use WiFi to upload their holiday snaps to Facebook, that little text has become a whole lot more expensive.

Just a quick plug in case you missed it... BBC's Horizon programme has just aired an episode entitled 'Strange Signals from Outer Space!' which examines the (so far unsuccessful) search for extra-terrestrial intelligence (SETI). It finishes with a look at star KIC 8462852 (also known as Tabby's Star) where astronomers believe that there may be the beginnings (or remnants) of a Dyson Sphere.

If you aren't familiar with the concept of a Dyson Sphere (which is nothing to do with vacuum cleaners), it's worth reading hard-fiction novel Pandora's Star by Peter F. Hamilton whose story begins with an astronomer discovering a star that suddenly and mysteriously vanishes. It is the supposition of the scientific community that it has been encased in one of the aforementioned Dyson Spheres by a civilisation far more powerful than humans.

An exploratory mission to visit the star causes it's equally unexplained reappearance but this, in turn, leads to potentially devastating implications for the human race. It's the first book in a series (as all sci-fi novels seem to be these days) but it comes with the Wireless Waffle 'big thumbs up' seal of approval.

It seems, however, that even the professionals are having difficulty in detecting any signals from remote solar systems. The Guardian newspaper reports that 'the most ambitious alien search to date draws a blank'. The Breakthrough Listen project had found a number of promising signals, however despite innovative software and algorithms and $100 million of funding, all of these turned out to be terrestrial in origin.

At the same time, whilst we are listening, should we not also be attempting to transmit signals for others out in the great black beyond to receive. After all, no-one would know that we are here unless we shout about it.

Many fear the consequences of us raising awareness of our existence. They claim that if we were to announce to the universe that we are here, 'minds immeasurably superior to ours would regard our Earth with envious eyes' (to paraphrase HG Wells). The 2015 Hugo award winning novel The Three-Body Problem by Cixin Liu explores this precise issue (as well as providing a tantalising glance of a futuristic on-line game designed to route out only the most intelligent). Originally written in Chinese, the book picks up the story of a remote Chinese 'radar' station whose function is not quite as navigational as it seems. It's in the process of being made into a feature length movie too (albeit in Chinese).

It stands to reason, however, that if we shy away from transmitting the occasional signal to alert anyone that is listening that we are here, it would be logical to assume that any other intelligent civilisations may have taken the same cautious approach. Hence we will never hear from them and they will not hear from us. This doesn't mean we should give up, but it does question the logic of listening intently, whilst not speaking.

It turns out that the planet Jupiter emits a range of different radio transmissions, not from people using mobile phones on the planet's surface, but so called long 'L' bursts and short 'S' bursts which are generated by the planet itself and its interaction with its moons, and that these signals are relatively easy to receive here on good old planet Earth. These emissions range in frequency from a few kHz to around 40 MHz. The Jovian signals get weaker the higher in frequency you go, but the lower frequencies are often absorbed by the Earth's ionosphere. In addition, many of these frequencies can be replete with short-wave transmissions. What is needed, therefore, is a frequency that is high enough to pass relatively unperturbed through the ionosphere, but low enough to be receiveable, without too much interference.

An obvious place to start would be the Radio Astronomy frequency allocation between 25.55 and 25.67 MHz as these frequencies should theoretically be free of all other radio transmissions. But it seems the frequency of preference for catching the latest bursts from Jupiter is actually 20.1 MHz, which is the frequency selected by NASA's Radio Jove project. From a radio spectrum perspective this is a relatively odd choice of frequency (e.g compared to the theoretically clean Radio Astronomy allocation). At an international level, frequencies around 20.1 MHz are allocated primarily to the fixed service, with a secondary allocation to mobile services. A quick scan of the Globaltuners database shows AT&T usage on 20.095 MHz and US Civil Air Patrol on 20.107 MHz. However, it seems that the signals from Jupiter at higher frequencies are much weaker, even by the time 25 MHz is reached.

So what do you need to listen to these mysterious signals? A simple short-wave radio should do the job, however it is said that there are two additional things which need to be done in order to tune in to Jupiter:

Turn off the AGC (automatic gain control) on the receiver. The AGC apparently tends to mask the bursts. A software radio is ideal for this.

Build a simple directional antenna.

The latter of these is the most difficult. A two-element array is what the experts say is needed, and at 20 MHz, this is roughly 8 metres (26 feet) square as the diagram on the right shows.

Notwithstanding a lack of the correct antenna, Wireless Waffle sought to attempt to receive Jovian radio signals using a short-wave receiver and a normal short-wave antenna (not the fancy two-element arrangement). Sadly, our attempts did not yield any L or S bursts that could be definitively identified as transmissions from Jupiter. We did however manage to receive:

So though we failed to receive any Jovian signals, we did receive some jovial ones and therefore maybe it wasn't such a pointless exercise as at first it might have seemed! Why not give it a go yourself and let us know how you get on?